Floor surfacing machine



Aug. 11, 1931. G JAcoBsoN E'r AL FLOOR SURFACING MACHINE Filed April 1l, 1927 #n.3- A TTORNEY 5 Sheets-Sheet l Aug. ll, 1931.y

G. JAcoBsoNT AL FLOOR SURFACING MACHINE FiledApril 11. 1927 5 Sheets-Sheet 2 Aug. 1l, 1931. G. JAcoBsoN E1' AL 1,818,954

FLOOR SURFACING MACHNE 3 vSheets-Sheet 3 Filed April l1, '1927 mm \N di?? RR.

Patented Aug. 11, 1931 UNITED sTATEs VPATENT OFFICE GUSTAV JACOBSON AND GUNNAB F. EBICSON, l' NEW YORK, N. Y., ASSINOBB T0 SUPERIOR FLOOR SURFACING IACHINE PORATION 0F NEW YORK CORPORATION, 0l' NEW YORK, Il'. Y., L 00B- ILOOB SURFAGING IACHINE Application llcd Apri! 11, 1927. erial I0. 188,507.

This invention relates to floor surfacing machines and aims to improve the construction and more particularly the operation of such machines.

The invention relates particularly to the type of floor surfacing machine which consists of a carriage which is pushed about by the operator, and has at its front end a rotary grinding drum. In the machines of this character now in use, it has been found that irregularities of the floor surface set up small but sustained vibrations in the grinding drum, which'cause an objectionable ripplelike surface in the floor.

A particular object of the present invention 1s to avoid such vibration of the grinding drum. This we accomplish by mounting the drum-on a lever or a pair of levers of the second or third class. The levers are fulcrumed to the carriage at their inner ends, and carry the drum at their outer ends. Means for varying the pressure on the drum and for raising it when required engage the levers at intermediate points between their fulcrums and the drum. This arrangement possesses several advantages. In the first place, the lever arm through which acts the weight of 'he drum, tending to hold the drum to the floor, is the entire length of the lever, 3o and may therefore be made several times as great as the radius of the drum without using an unduly long lever or carriage. This gives the weight of the drum an effect on the position of the'lever materially greater than that of the forces set up by changes in the friction between the drum and the floor, which act through an arm equal in length to the radius of the drum. A second advantage is that in such a lever of the second or third class, there are not, as in the case of a lever of the -first class, balancing forces which tend to sustain any vibrations which may occur in the drum. A third advantage is that the use of a lever fulcrumed at its inner end facilitates placing the shaft, from which power is obtained to rotate the drum, close to the fulcrum point of the lever. A feature of the invention consists in driving the drum through a chain whose driving sprocket is mounted on a shaft 00 close behind the fulcrum of the lever, so that movements of the lever about its fulcrum cause substantially no change in tension of the chain. This prevents up-and-down movements of the drum, caused by irregularities in the lloor, from causing irre larity in the driving force rotating the rum, and thus tends to prevent the forming of a ripple-like surface.

A further object of the invention is to provide improved control means for regulating the pressure on the drum, and for ralsing-,thc drum when desired. This and other features of the invention may best be understood from a detailed description of a practical floor surfacmg machine embodying the invention, which is shown in the accompanying drawings, in which:

1 is a side view of the machine;

Fig. 2 is a longitudinal section of the ma.- chine taken on the line 2-2 of Fig. 3

Fig. 3 is a horizontal section of t e machine taken on the line 3-3 of Fig. 2;

Fig. 4 is a partial transverse section of the machine taken on the line 4-4 of Fig. 2, indicating the drum and omitting other parts be ond'the section plane; and

1g. is a fragmentary transverse section on the line 5-5 of Fig. 2, showing one of the drum bearings.

The machine illustrated includes a carriage 10 having a platform 11 and depending side flanges 12, 12 which are secured to the platform by means of stii'ening angles 13. The carriage has between its side flanges, near its front end, a pair of wheels 14, 14 freely journalled on a bent shaft 15 extendin between the side ianges.V The rear end o the carrlage 1s supported on a caster 16 mounted on a rearward projection 17 of a bracket 18, which extends across the rear end of the carnage and provides also a rearwardly and upwardl inclined projection 19, to which is attache a handle 20, by means of which the carriage is pushed about the floor by the operator.

A grinding drum 30 is mounted at the front end of the carriage. It consists of a hollow metal cylinder provided with an abrasive surface. Its shaft 31 has its ends journalled in self-aligning ball bearings 32 in the diskl* shaped outer portions 33 of a pair of levers 34, 34. These levers are fulcrumed to the carriage at their inner ends by meansof pivots 35, 35 vprojectin outwardly from the side flanges 12, 12' o the carriage. The length of each lever is several times as great as t e radius of the drum 30. Just inside the drum, the levers ,are connected by means of the grinding drumand the oor; also to raise the drum clear of the Hoor, so that the ma i chine may be moved yabout easily when not in operation. Such means include a forked lever 40, which is fulcrumed to the side ianges 12, 12' by means lof pivotbolts 41, 41' which pass through the two forwardly projecting arms v42, 42 of the forked lever. The arms 42, 42' carry at theirouter ends blocks 43, 43 (which'may be formed integral with the arms as shown) containing vertlcal holes. Tension rods 44, 44' fit loosely in the holes in the blocks 43, 43', and have attheir upper ends, enlarged heads or nuts 45 resting on the upper surfaces of the blocks 43, 43.

j The lower ends of the tension rods 44, 44' are secured in the tie rod 37 inside the side flanges 12, 12' and at opposite sides of the universal joint 38. Compression springs 46, 46 surround the tension rods 44, 44|', so that they may react betweenthe blocks 43, 43' and the tie rod 37er nuts 48 set on the tension rodsjust above the tie rod.

It is apparent that if the lever 40 be tilted so as to cause the blocks 43, 43' at its outer end to move downward, each of the springs 46, 46 is compressed so as to urge each end of the grinding drum 30 a ainst the y iloor more and more strongly. In t is movement, each of the blocks sl1 s down along the tension rod which passes through it. When the outer end of the lever is raised to bring the blocks into contact with the heads 45 of the tension rods, the downward pressure of the springs on the drum is at a minimum. By adjustment in the position ofthe heads 45 or the nuts 48, this minimum may be made whatever is -re uired; or, if desired, the adjustment may such that the springs are fully expanded when the blocks 43, 43' are in contact with the heads 45, so that the drum is held down by its own welght only. When the outer ends of the lever 40 are raised beyond the point at which the heads 45 of the tension rods come into contact with the blocks, the blocks raise the tension rods and lift the grinding drum clear of the floor. .l

Such movements of the lever 40. are obtained by manipulation of a handle 50, pivoted to the handle'20 .near its upper end. The handle 50 is connected with the lever 40 by force-increasing mechanism to facilitate compressing the springs 46, 46', or raising the drum 30 by means of the handle. Such mechanism includes a link 51, whose upper end is pivoted to the handle 50 at 52, and whose lower end is pivoted at 53 to the rear end of an arm 54, which is xed to, and extends rearwardly from, a gear segment 55 journalled at 56 to the dependln flange 57 of an an le plate 58.. secured to the ttom of the plat orm 11. The (gear segment 55 meshes wlth a corres on ing gear segment 59, journalled on the ange 57 at 60. To this gear segment 59, the rear end of the forked lever 40 is connected by means of a pivot bolt 61 projecting from the segment between its axis and its teeth and passing through aslot 62 in the lever. I When the handle 50 is allowed to stay in its normall position, shown in Fig. 1, the grinding drum rests on the floor, either under its own weight only or with the addition of a minimum spring pressure. When the handle 50 is pushed downward from its normal position the rear end of the forked lever 40 1s raised and its forward end is de ressed to compress the springs 46, 46', an thus increase the downward pressure on the drum. 'lheuexact amount of the pressure obtained durintg the operation of the machine may, there' ore, be regulated by pushin down to a eater or less extent on the han le 50.

henthe handle' 50 is raised from its normal position, the outer end of the lever 40 is raised, drawing'up the tension rods 44,44', and lifting the grinding. drum off the floor into an inoperative position.- A notch 63 in an arc 64, secured to the handle 20, may be provided for holding the drum off the floor gy cooperation with a latch 65 on the han- The inding drum 30 is rotated b means `of ane ectric motor 70, mounted on t e latform 11 of the carriage. Through a c ain 7l, this motor drives a shaft 72 extending across the carria e and journalled in its side anges 12, 12'. rom a sprocket 73 ixedon the shaft 72, the power is transferred to a sprocket 74 fixed on the drum shaft 31 by means of a chain .7 5. It should be particularly noted that the driving shaft 72 is located close to the fulcrum 35, 35' at the rear ends of the lever 34, 34 and directly behind the rear ends of the levers, so that up-anddown movements of the drum 30, and corresponding movements of the levers 34, 34' have ractically no effect upon the tension o the c ain 75. This prevents up-and-do'wn movements of the drum, which maybe caused Yby irregularities in the floor surface, from making the rotation of the drum uneven.

The dust produced by the drum in grinding is directed by the drum into a dust pan 80 located just inside the drum. The outer ends of this pan are secured to the levers 34, 34 by strips of sheet metal 81, which bend so easily that the pan does not interfere with independent up-and-down movement of the s two levers. The dust is drawn from the pan 80 by a suction blower 82 driven by the motor 70 and is deposited in a bag 83, indicated in dot-and-dash lines in Fig. 1. A pipe 84 connecting` the bag with the blower has a flexible portion 85 so as not to interfere with free movement of the levers 34, 34.

What is claimed is: 1. In a ioor surfacing machine having a carriage and a rotary grinding drum at the front end of the carriage and movable vertically, drum-controlling mechanism comprising two intermeshing gear segments pivotally mounted on the carriage, one of which has an arm projecting rearwardly from its axis,

. a control handle connected to said arm, and

a lever fulcrumed on the carriage and having its rear end pivotally connected to the other gear segment between the axis and the teeth of the gear segment, the front end of said lever being operatively connected to the drum.

2. In a Hoor surfacing machine having a carriage and a rotary grinding drum at the front end of the carriage separately vertical-` ly movable mountings for the two ends of said grindingi drum, and drum-controlling mechanism comprising two intermeshing gear segments pivotally mounted on the carriage, one of which has an arm pro'ecting rearwardly 'from its axis, a control ndle connected to said arm, a forked lever fulcrumed on the carriage and having its single rear end ivoted to the other gear segment between t e axis and the teeth of the gear 4o segment, rods extendin downward through openings in the forke front endsl of said lever and connected to said drum mountings nuts on said rods above the lever ends, an compression springs on said rods below the lever ends.

In testimony whereof we have hereunto set our hands.

' GUSTAV JACOBSON. GUNNAR F. ERICSON. 

